graph TD
A[Trip Generation] --> B[Trip Distribution]
B --> C[Mode Choice]
C --> D[Route Assignment]
A transport models from first principles can be expressed in 4 stages, according the classic four-step model:
graph TD
A[Trip Generation] --> B[Trip Distribution]
B --> C[Mode Choice]
C --> D[Route Assignment]
The dependency structure may be more realistic, with trip generation, distribution and mode choice all affected by the network.
graph TD
E[Network] --> D[Route Assignment: s4]
F[Other Factors] --> C
F --> B
C --> D
D --> B
E --> B[Trip Distribution: s2]
E --> C[Mode Choice: s3]
B --> C
B --> A[Trip Generation: s1]
We should not throw the baby out with the bathwater, but reform, rebuild or retrofit transport modelling for the 21st Century.
Let’s build a transport model, simplifying the 4-stage model by collapsing Trip Generation and Distribution into a single stage: Trip Estimation.
flow = pop * jobs * exp(beta * distance)Results:
pct package.pcycle = pct::uptake_pct_godutch_2020(distance, gradient)Route network summarising the Go Dutch scenario, showing potential for cycling.
dodgr.